Nice with apple pie but it will not differentiate the the OVF & EVF. For this you need to compare a bicycle vs motorcycle or bicycle vs a car....

We can use EVF like OVF by just turning off the LiveView, but there is no way to use OVF as EVF

Not exactly true. To someone who prefers looking at an optical image over an electronic image --- The EVF never fully compensates for an optical image.

And while some day, processing and buffer speeds may increase... In fast burst shooting, EVFs currently lag and produce a slide-show as opposed to a live image.

Well in multidimensional OVF, Not all the light reaches to the eyes. Normal mirror can only reflects 80 to 85% of light and only silver/gold plated mirrors can reflect 90 to 95% of light. So if you have pentaprism or pentamirror OVF, you will loose 10 to 20% of light in every single dimension and after all the processing via OVF you will only receive 40 to 50% of light. This is the only reason why low end cameras have 95% coverage. A high end OVF with 70 to 80% output would cost more than $600.Also, reflection, optics, and water slows down the speed of light to 124,000 miles per hour. Scientist have also proved the effect on speed of light by optics and other objects. They managed to slow the light speed upto 9.7km/s in 2004. The results in your eye will not be as fast as you think.

If A65 or A77 can save a minimum of 8 images of 24mp each per-second and still have some left in buffer than I can imagine their processing speed will be around 12 images per second. Means they can process 288 mega-pixel per second. So to populate a 2.4million dots of EVF requires 2.4mp of image so the total reaction time or delay on an EVF is not more than 1/120 or 0.008333 second. The normal reaction time of a human is 1/5 or 0.20 second if not drunk!!!

All sounds good, but if you've ever shot a burst tracking a subject the EVF cameras up to this point still blackout enough to distract you. Too much of a delay. Also I get 0 FPS when my EVF has chewed up all my battery. I like a bright OVF during the day, and an EVF at night. Be neat to have both.